CN202770479U - Variable-frequency magnetic flow meter - Google Patents
Variable-frequency magnetic flow meter Download PDFInfo
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- CN202770479U CN202770479U CN2012202023536U CN201220202353U CN202770479U CN 202770479 U CN202770479 U CN 202770479U CN 2012202023536 U CN2012202023536 U CN 2012202023536U CN 201220202353 U CN201220202353 U CN 201220202353U CN 202770479 U CN202770479 U CN 202770479U
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- G—PHYSICS
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- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/56—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects
- G01F1/58—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects by electromagnetic flowmeters
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/56—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/56—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects
- G01F1/58—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using electric or magnetic effects by electromagnetic flowmeters
- G01F1/60—Circuits therefor
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Abstract
The utility model discloses a variable-frequency magnetic flow meter. The variable-frequency magnetic flow meter comprises a pipeline part for a process flow, a coil for generating a magnetic field on the pipeline part, a current source for exciting the coil to generate the magnetic field, and an electrode for detecting electrodynamic potentials induced by the magnetic field on the process flow, wherein the current source excites the coil with a plurality of different pulse frequencies; and a processor calculates a function of electrodynamic potentials at the different pulse frequencies and generates flow output based on the function.
Description
Technical field
The utility model relates generally to fluid treatment, and particularly, relates to process flow measurement and control.Especially, the utility model relates to the measuring technique for magnetic flowmeter.
Background technology
Magnetic flowmeter (or magnetic meter (mag meter)) is by faraday's induction, galvanomagnetic effect measuring flow.The flowmeter drive coil is producing magnetic field at pipe section, and magnetic field induction electromotive force (EMF) on process streams.Use extends through pipe section and enters the pair of electrodes of process streams or measure the electric potential difference (or voltage) of generation by capacitive couplings.Flow velocity and induction electromotive force are proportional, and volume flow rate and flow velocity and area of passage are proportional.
Generally speaking, the electromagnetic flow-measurement technology can be applied to water-based fluid, solion and other conduction flow.Concrete purposes comprises sewage treatment facility, high purity chemical production, wholesome food and beverage production and chemical treatment, comprises dangerous and corrosivity process streams.Magnetic flowmeter also is used in the hydrocarbon fuel industry, comprises the hydraulic fracturing technology that utilizes grinding and corrosivity mud, and other oil-gas minings and job operation.
Magnetic flowmeter is therein because relevant pressure drop (for example, on orifice plate or Venturi tube) and so that provide fast, accurately flow measurement in based on the unwelcome application of the technology of pressure reduction.When mechanical organ is introduced process streams be difficulty or when unrealistic, also can use the magnetic meter, such as turbine rotor, eddy current come off element or pitot tube.
In these are used, exist improving the lasting needs of magnetic flow measurement technology.Especially, there is the demand that in the high-precision applications of the process noise impact that stands to comprise that electronics, machinery and electromagnetic noise affect, reduces the deviation of flow measurement.
The utility model content
According to an aspect of the present utility model, a kind of magnetic flowmeter is provided, comprising: the pipe section that is used for process streams; Coil is used for producing magnetic field at pipe section; Current source is used for drive coil to produce magnetic field, and wherein current source is with a plurality of different pulse frequency drive coils; Electrode, for detection of on process streams by the electromotive force of magnetic field induction; And processor, be used for calculating the function at the electromotive force at described a plurality of different pulse frequencies place, and be used for producing flow output based on described function.
According to embodiment of the present utility model, preferably, in above-mentioned magnetic flowmeter, described a plurality of different pulse frequencies can comprise at least three different pulse frequencies.Preferably, in above-mentioned magnetic flowmeter, electrode detection is at the electromotive force at a plurality of outs of phase place.
According to another aspect of the present utility model, a kind of magnetic flowmeter is provided, comprising: pipe section, pipe section have internal diameter and external diameter; Coil is near the external diameter of pipe section; Be connected to the pulsed current source of coil, wherein the pulsed current source provides a plurality of different pulse frequencies; Electrode extends to the internal diameter of pipe section, wherein the electromotive force of electrode detection on pipe section from the external diameter of pipe section; With the processor that is connected to electrode, wherein processor produces conduct in the flow output of the function of the electromotive force at described a plurality of different pulse frequencies place.
According to embodiment of the present utility model, preferably, above-mentioned magnetic flowmeter can also be included in the lining on the internal diameter of pipe section, and wherein electrode extends through lining and flows with contact process.
Description of drawings
Fig. 1 is the schematic side elevation of the magnetic flowmeter in the flanged (FLGD) embodiment with one installation transmitter.
Fig. 2 is the schematic end of the magnetic flowmeter in the embodiment of the wafer type with Remote Installation transmitter.
Fig. 3 is the wiring diagram be used to the magnetic flowmeter with variable-frequency pulse formula current source.
Fig. 4 is the curve map of variable-frequency pulse current signal.
Fig. 5 is that explanation is used for the process flow diagram with the method for frequency conversion magnetic flowmeter measuring flow.
Embodiment
Fig. 1 is the schematic side elevation of an embodiment of the magnetic flowmeter 10 in the flange configuration with integrative installation technology transmitter 12.Flowmeter 10 comprises sensor housing 14 and pipe section 16, and coil 18 and electrode 20 (shown in the dotted line) are arranged in sensor housing 14.Transmitter 12 comprises shell of transducer 22, and shell of transducer 22 is with circuit board (or controller) 24 (also with shown in the dotted line), and local operator interface (LOI) 26.As described below, controller 24 produces the variable-frequency pulse formula exciting current that is used for coil 18, in standing the environment of process noise, improves performance and reduces deviation of signal.
In the integrative installation technology embodiment of Fig. 1, transmitter 12 directly is installed on the interface section 14A of sensor housing 14, carries out directly inner the connection between controller 24, coil 18 and electrode 20.Replacedly, transmitter 12 is remotely installed and connected is outside, as shown in Figure 2.
In the flange embodiment of Fig. 1, pipe section 16 comprises through hole flange 28, is used for adopting the flange 28A at transportation and installation process support flowmeter 10 that magnetic flowmeter 10 is installed in pipeline (piperun) or other fluidal textures.According to embodiment, flange 28 can be formed by stainless steel material (for example, as being used for pipe section 16) or carbon steel material (as being used for sensor housing 14).Replacedly, in sensor housing 14, pipe section 16 and the flange 28 any one can be formed by carbon steel, stainless steel, aluminium, copper, brass or other metal or metal alloy, or formed by durable polymer or thermoplastic, such as PVC (Polyvinylchloride) or ABS (acrylonitrile-butadiene-styrene (ABS)).
Shell of transducer 22 comprises the protecgulum 34 for electronic component plate 24 and local operator interface 26, and is used for transmitter 12 is connected to the pipe joint element 36 of power supply (PS) 40 and process control unit (PCU) 42.Power supply 40 comprises interchange (line) or direct supply, or the two.Process control unit 42 comprises remote communication devices, long-distance operating device or Process Control System, and it is used to the output from magnetic flowmeter 10, to monitor or the control procedure variable, includes but are not limited to, by the flow of pipe section 16.
In TW two wire embodiment, transmitter 12 adapts to a series of different communication protocol, include but not limited to, standard analog (4-20 milliampere) signal, analog to digital hybrid protocol (such as
) and digitized measurement and control framework (comprise Foundation
TMFieldbus,
BUS/
NET and
).Replacedly, transmitter 12 utilizes loop circuit, cable, control bus and data line or is used for radio frequency), the combination of the wave point of infrared (IR) or optical communication.In the embodiment of these and other, suitable transmitter 12 and magnetic flowmeter 10 can obtain from Rosemount company and the Emerson Process Management company in Minnesota State EdenPrairie city, have improvement described here.
Fig. 2 is the schematic side elevation of the magnetic flowmeter 10 in wafer type (without the flange) configuration with Remote Installation transmitter 12.Depend on embodiment, magnetic flowmeter 10 also adopts additional mounting structure, including, but not limited to, alignment ring, threaded crimp contact and the ring-like Connection Element of outer cover.
Do not have near the pipe section 16 therein in the limited installation of sufficient space, the Remote Installation of Fig. 2 configuration allow transmitter 12 be located at procedure structure such as beam, wall or partition near, or be positioned on another stream pipe or the conduit.Replacedly, transmitter 12 can be orientated range sensor housing 14 as and reach 1000 feet (being roughly equal to 240 meters) or more, for example is used for adapting to more concentrating or accessible transmitter is arranged, or transmitter 12 is positioned in the outer pulpit of process environment.
In order to comprise each of these embodiment, the term " flowmeter " that here uses can not only comprise pipe section 16, sensor housing 14 with and internal part, and comprise transmitter 12 and parts thereof.Especially, " flowmeter " can comprise one installation and the Remote Installation embodiment of transmitter 12, and no matter the connecting length between transmitter 12 and the sensor housing 14, and no matter form the particular form that connects.
In the end-view of Fig. 2, pipe section 16 (showing with cross hatch) axially extends through sensor housing 14, and sensor housing 14 forms the annular casing that centers on pipe section 16, coil 18 and electrode 20.Magnetic field B laterally orientation strides across pipe section 16, the approximate vertical process streams.
Electronic component plate (or controller) 24 comprises processor or microprocessor (μ P) 24A and variable-frequency power sources (VFDC) 24B.Processor 24A comprises interface, and this interface is used for being connected to Process Control System or long-distance operating device and is used for transmitting representative by the output of the flow of pipe section 16.
The all parts of controller 24, local operator interface 26 and terminal block 28 can be arranged to different electronic component plates or the form of circuit component, as shown in Figure 2, or is arranged to integrated electronic component or storehouse.In addition, controller 24 also can be configured to switch between the internal electric source that is used for frequency conversion current source 24B and external power source.In certain embodiments, as shown in Figure 1, magnetic flowmeter 10 utilizes external power source 40, and it provides interchange or DC current by frequency conversion current source 24B switching, chopping or modulation.
In each of these enforcements, frequency conversion current source 24B provides the pulse excitation electric current to coil 18, and this electric current is by with a plurality of different frequency choppings.Electrode 20 detects the electromotive force of responding in process streams, and processor 24A is based on the function calculation flow output at the electromotive force at a plurality of different pulse frequencies place.In the ordinary course of things, this function comprises average, weighted mean or other average functions such as the electromotive force signal of responding at each different pulsed frequency place,, to reduce the deviation of signal that causes owing to noise effect as described below.
More particularly, coil 18 is configured to produce roughly uniform magnetic field B in pipe section 16 inside.The line of flux is across pipe section 16 and lining 44 orientations, and as shown in Figure 2, (that is, with approximately 90 °) intersect with process streams on approximate vertical or normal direction.On relatively wide opereating specification, magnetic field intensity (or magnetic density) is about and exciting current is proportional, and exciting current is switching on and off magnetic field by frequency conversion current source 24B when coil 18 sends pulse signal.
When conductive process stream flows through magnetic field B, form faraday's ring at electrode 20.The induction electromotive force (or faraday's voltage) that electrode 20 detects on the pipe section 16, wherein induction electromotive force and flow velocity and magnetic field intensity are roughly proportional.
In mathematical form, the inside diameter D of induced potential E and mean flow rate V, average magnetic field intensity B and the runner that limited by lining 44 is proportional:
E=kVBD [1]
" K factor " is to depend on the proportionality constant of measuring the unit that E, V, B and D adopt (K).
Conversion formula 1, flow velocity V provides as the function of induced potential E, magnetic field intensity B and flow diameter D:
V=E/kBD [2]
Volumetric flow rate equals mean flow rate and multiply by area of passage.
Fig. 3 is the schematic wiring diagram for magnetic flowmeter 10.In this embodiment, as mentioned above, electrode 20 extends through pipe section 16 and lining 44 to detect the electromotive force by the flow of process fluid induction of crossing magnetic field B.Terminal block 48 is connected to processor 24A electrode 20 and power supply 24B is connected to coil 18.
In order to improve precision, magnetic flowmeter 10 is arranged to pulsed DC (direct current) operation.In this pattern, processor 24A relatively comes the electromotive force signal in maximum (peak value) and minimum (approaching zero) place, magnetic field induction of self-electrode 20, to correct skew and zero point drift.The pulsed direct current measurement also reduce electrolytic reaction between process fluid and the electrode 20, to the capacitive couplings of coil 18, based on the phase shift of impedance and comprise magnetic field and process fluid or electrode signal line between the impact of quadrature effect (quadrature contribution) of inductive coupling.
Frequency conversion current source 24B also changes pulse current frequency to reduce the process noise impact.In certain embodiments, processor 24A timing (clocks) current source 24B is with regulating impulse frequency or dutycycle, as shown in Figure 3.Replacedly, current source 24B comprises internal pulses modulation circuit parts, or is used for regularly door or the clock of external current source, as mentioned above.
Fig. 4 is the curve map of variable-frequency pulse current signal I, with produced simultaneously process noise signal N.Each current impulse is limited by pulse-response amplitude A, pulse width W (or W ') and recurrence interval T (or T ', T ").Recurrence interval T limits pulsed frequency (f=1/T), and provides dutycycle (that is, dutycycle=W/T, or ground of equal value, dutycycle=Wf) by pulse width W divided by recurrence interval T.
The current impulse amplitude A depends on coil resistance and input voltage, and input voltage is usually from 10V to 40V or more changeableization.In certain embodiments, pulse current I is strict DC (direct current) signal, and coil current and magnetic field have (pulse) polarity of constant.In other embodiments, use AC (alternating current) source, or electronic component is introduced displacement or is offset to produce pulse AC signal in coil 18.In these embodiments, coil current and magnetic field reverse direction periodically.
Noise signal N is produced by multiple not same-action.These effects comprise from electronics ripple and the infiltration (bleed-through) of line power and other AC signal and come pressure or the flow pulsation (flow pulsation) of self-pumping, compressor, turbine and other whirligigs.Noise signal N also is independent of other source by the mechanical vibration in pipe section and other procedure structures or produces with other source combinations.
In the specific embodiment of Fig. 4, first group of current impulse has pulse width W and the cycle T of approximately constant, has the frequency f corresponding to prevailing noise signal.Measure induction electromotive force at sampling phase S place, sampling phase S is defined as a part or the mark of recurrence interval T as the basis take pulse one by one.Usually, be arranged on after roughly maximal value is sentenced in magnetic field, approached in each current impulse and select sampling phase S when finishing.
When noise signal N coupling sample frequency, flow measurement is subject to deviation effects, because each sample " reads " same phase of noise signal, causes the constant displacement towards higher or lower value.When noise and sample frequency were harmonic relationships (harmonic relationship), effect was similarly, particularly for leading roughly single order, three rank and other odd-order harmonics of the Fourier transform of square wave pulsed current signal I.Yet because beat generation (beat generation) and other disturbing effects, deviation effects also can occur in anharmonic wave sampling and noise frequency place.
Therefore, no matter the particular form of noise signal N, the constant frequency sampling enters flow measurement with deviation usually.Especially, when pump and other turbomachinery circulation opening and closing, or when the specific noise frequency when sample frequency (or its harmonic wave) changes, may introduce deviation.Even the high-power machinery device is not in the situation that there is direct Coupled with Flow can produce noise yet,, for example, by in flow duct and other procedure structure, bringing out mechanical vibration, or by the infiltration on the line power (bleed-through).
In order to reduce these impacts, the pulsed frequency of coil current changes, as shown in Figure 4.Especially, pulse width is that W and recurrence interval T can change independently, thereby increases or reduce pulsed frequency with fixed width or fixed duty cycle, and perhaps the function as frequency changes pulse width and dutycycle.As a result, sampling phase S changes with respect to noise signal N, reduces deviation by in the scope of out of phase and corresponding amplitude noise being sampled.
In the specific example of Fig. 4, the relatively low and current impulse of coil inductance has long " smooth " or Ping Qu or plateau region (plateau region) in most of pulse width W.In this case, also can be independent of recurrence interval T and adjust sampling phase S.In other configuration, in particular to larger caliber, stabilization time can be longer, and plateau region can relative narrower, and this need to increase pulse width W.
Fig. 5 is process flow diagram, and the method 50 that is used for using frequency conversion magnetic flowmeter measuring flow is described.Method 50 is included in and produces pulsed magnetic field (step 52) on the process streams, detects by the electromotive force (step 54) of magnetic field induction, the frequency (step 56) that changes pulsed magnetic field, calculating at the average function (step 58) of the electromotive force at a plurality of different frequencies place with based on average delivery rate measured value (step 60).
In certain embodiments, method 50 also comprises weighted frequency (step 62) to produce weighted mean (weighted average), for example stands one or more frequencies of the deviation that noise causes with eliminating.In other embodiments, method 50 comprises that change sampling phase (step 64) and weighted phases (step 66) are to produce weighted mean.In further embodiment, method 50 comprises based on the deviation of comparing with average or average of the electromotive force at characteristic frequency or phase place place or difference generation alarm (step 68).
Produce pulsed magnetic field (step 52) and comprise that drive coil or other field sources are to produce pulsed magnetic field in process streams.As described in describing for Fig. 4 as mentioned, magnetic signature is determined by current impulse amplitude, pulse width and pulsed frequency.
Detect electromotive force (step 54) and comprise that the pair of electrodes of for example using (Fig. 2) on the stream pipe that is positioned at lining detects voltage or the electric potential difference by magnetic field induction.Electric potential difference (being induction electromotive force) changes with magnetic field intensity and mean flow rate, typically with the substantial linear variation.
The frequency (step 56) that changes pulsed magnetic field comprises that the frequency that changes excitation current source is to produce a plurality of different pulsed frequencies.As mentioned above, depend on additional parameter, such as coil inductance and flowmeter geometric configuration, shape and the pulsed frequency of magnetic field pulse shape and the pulse of pulsed frequency follow current.
In certain embodiments, be independent of pulse width, change pulsed frequency by changing the recurrence interval, and dutycycle increase correspondingly or reduces.In other embodiments, pulse width also changes, and pulsed frequency and dutycycle are independently.
In typical embodiment, produce at least three different pulsed frequencies.In the ordinary course of things, the sample frequency interval so that harmonic wave is not overlapping, or makes one group of harmonic wave and other group harmonic wave not overlapping.The harmonic wave sampling of this repetition by avoiding noise signal and further reduce deviation.
Calculate the average function that average (step 58) comprises the electromotive force that limits a plurality of different pulse frequencies place.In certain embodiments, average function is included in common (not weighting) average of the electromotive force at each different frequency place, and each base value (contribution) equates weights.At other embodiment, average function comprises weighted mean (weighted mean) or the weighted mean based on different frequency and phase place base value (phase contribution), and is as described below.In a further embodiment, average function comprises from the base value between different sampling periods, for example, the continuous strand average that obtains two, three or more continuous sampling cycle, or comprise the time weighted average that wherein gives the base value weights based on the relative sampling time.
Produce output (step 60) and comprise the output signal that produces representative process flow based on average function.Especially, described output is based at a plurality of different pulse frequencies place rather than average, average or the weighted mean of the electromotive force at individual pulse frequency place.
Weighted frequency (step 62) comprises that the electromotive force with each pulsed frequency place induction compares with common average (common mean), limit the difference that is used for each pulsed frequency between COMMON MEAN and the electromotive force, and based on the difference weighted mean.Described difference differently is defined as with respect to the absolute of average or relative (%) deviation, or limits by statistical method, and statistical method for example is the z-mark based on standard deviation, or based on possibility or the probability of deviation or z-mark.
In one embodiment, weights are 0 or 1.This is voting or rejection technology basically, and wherein, the electromotive force value in the particular range of average is assigned unified relative weights 1, and beyond this scope those are assigned weights 0.Therefore, therefore 0 weighted value is got rid of by " rejection " or from flow output, and 1 weighted value is included.
In certain embodiments, when differing accuracy rating above flowmeter with the corresponding electromotive force of characteristic frequency and average, this characteristic frequency is vetoed or is got rid of.For high-precision applications, accuracy rating can be 1% or lower, for example approximately 0.2%.In other embodiments, differ the standard deviation interval of selecting quantity when the corresponding electromotive force of characteristic frequency and average, for example, differ one, two or three, or when the probability of electromotive force or possibility (for example, based on the stochastic sampling hypothesis) when being less than certain threshold level, for example 1%, 5% or 10%, this characteristic frequency is vetoed or is got rid of.
In a further embodiment, repeat statistical study at the sample that reduces, verifying remaining measurement, and get rid of any extra frequency that basically is different from new average.Replacedly, use the average of continuous weighting, wherein weights are limited by possibility or probability function, as mentioned above, have the relative weights between 0 and 1.
Detect electromotive force at the out of phase place and further reduce deviation, because the more complete sample of its production process stream, comprise out of phase and the amplitude of noise contribution.In certain embodiments, flow output based on as in common (perhaps not weighting) average of the electromotive force of each independent phase place place sampling.In other embodiments, described output comprises the weighted mean (weighted mean) (step 62) of out of phase base value, wherein weights based on difference or the deviation of average (or COMMON MEAN), as mentioned for as described in the frequency weighting (step 66).
Therefore, depend on embodiment, flow function can be included in a plurality of different frequencies or at the average of the electromotive force at a plurality of different frequencies and a plurality of outs of phase place.Flow output can comprise again COMMON MEAN, average or the weighted mean based on different frequency and phase place base value.
In certain embodiments, processor produces the flow measurement of the variable frequency of deviation reduction, need not extra operator's input or configuration requirement, no matter and the character of noise signal itself or source.For example, when pump or other noise sources were introduced in the procedures system, average function automatically reduced the deviation in the flowmeter output, no matter whether identifies noise source.Deviation is further reduced by frequency and phase weighting, and the variation (for example, when pump or turbine trip speed variation) that this automatically adapts in the noise spectrum need not frequency matching, phase place locking and other sophisticated signal treatment technologies.
At some embodiment, when the deviation of any frequency or phase component surpasses certain threshold level, based on its poor with common average or average, produce warning output or alarm indication (step 68).In the ordinary course of things, alert threshold can be corresponding to the rejection threshold value, and as mentioned above (for example, number percent or sigma deviation, or possibility), but alarm signal is independent of frequency or phase weighting.Therefore, can produce based on the deviation of characteristic frequency or phase place base value and average the alarm indication, no matter whether deviation is used for being weighted in the average that uses in the flow measurement output.
Although reference example embodiment has described the utility model, it will be understood by those skilled in the art that can be in the situation that do not deviate from scope of the present utility model and carry out various variations and replace its element with equivalent.In addition, in the situation that do not deviate from essential scope of the present utility model, can make and revising so that special circumstances or material adapt to teaching of the present utility model.Therefore, the utility model is not limited to specific embodiment disclosed herein, but comprises the whole embodiment in the scope of comprising that fall into attached claim.
Claims (5)
1. magnetic flowmeter is characterized in that comprising:
The pipe section that is used for process streams;
Coil is used for producing magnetic field at pipe section;
Current source is used for drive coil to produce magnetic field, and wherein current source is with a plurality of different pulse frequency drive coils;
Electrode, for detection of on process streams by the electromotive force of magnetic field induction; With
Processor is used for calculating the function at the electromotive force at described a plurality of different pulse frequencies place, and is used for producing flow output based on described function.
2. magnetic flowmeter according to claim 1, wherein said a plurality of different pulse frequencies comprise at least three different pulse frequencies.
3. magnetic flowmeter according to claim 1, wherein electrode detection is at the electromotive force at a plurality of outs of phase place.
4. magnetic flowmeter is characterized in that comprising:
Pipe section, pipe section have internal diameter and external diameter;
Coil is near the external diameter of pipe section;
Be connected to the pulsed current source of coil, wherein the pulsed current source provides a plurality of different pulse frequencies;
Electrode extends to the internal diameter of pipe section, wherein the electromotive force of electrode detection on pipe section from the external diameter of pipe section; With
Be connected to the processor of electrode, wherein processor produces conduct in the flow output of the function of the electromotive force at described a plurality of different pulse frequencies place.
5. magnetic flowmeter according to claim 4 also is included in the lining on the internal diameter of pipe section, and wherein electrode extends through lining and flows with contact process.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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US13/135,182 US9182258B2 (en) | 2011-06-28 | 2011-06-28 | Variable frequency magnetic flowmeter |
US13/135,182 | 2011-06-28 |
Publications (1)
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CN202770479U true CN202770479U (en) | 2013-03-06 |
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CN2012202023536U Expired - Fee Related CN202770479U (en) | 2011-06-28 | 2012-05-08 | Variable-frequency magnetic flow meter |
CN201210140594.7A Active CN102853869B (en) | 2011-06-28 | 2012-05-08 | Variable frequency magnetic flowmeter |
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CN201210140594.7A Active CN102853869B (en) | 2011-06-28 | 2012-05-08 | Variable frequency magnetic flowmeter |
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US (1) | US9182258B2 (en) |
EP (1) | EP2726826B1 (en) |
JP (1) | JP6114267B2 (en) |
CN (2) | CN202770479U (en) |
CA (1) | CA2835049A1 (en) |
RU (1) | RU2584069C2 (en) |
WO (1) | WO2013003021A1 (en) |
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CN102853869A (en) * | 2011-06-28 | 2013-01-02 | 罗斯蒙德公司 | Variable frequency magnetic flowmeter |
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- 2012-06-12 JP JP2014518603A patent/JP6114267B2/en not_active Expired - Fee Related
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CN102853869B (en) * | 2011-06-28 | 2016-12-21 | 微动公司 | Variable frequency magnetic flowmeter |
Also Published As
Publication number | Publication date |
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US20130006544A1 (en) | 2013-01-03 |
EP2726826B1 (en) | 2023-05-24 |
EP2726826A4 (en) | 2015-04-01 |
RU2013157314A (en) | 2015-06-27 |
CA2835049A1 (en) | 2013-01-03 |
WO2013003021A1 (en) | 2013-01-03 |
JP6114267B2 (en) | 2017-04-12 |
CN102853869A (en) | 2013-01-02 |
RU2584069C2 (en) | 2016-05-20 |
US9182258B2 (en) | 2015-11-10 |
JP2014518392A (en) | 2014-07-28 |
CN102853869B (en) | 2016-12-21 |
EP2726826A1 (en) | 2014-05-07 |
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